Traditionally, there have been mechanical connections between a vehicle accelerator pedal and the vehicle engine. These mechanical connections typically include throttle cables that move in response to the accelerator pedal being actuated by an operator. Movement of the throttle cable controls the engine output power based on the amount of force the operator has applied to the accelerator pedal.
The automotive industry is constantly trying to eliminate mechanical connections by incorporating electronically controlled systems into vehicles. One such system is the electronic throttle control (ETC) system. An ETC generates an electronic signal that is representative of pedal position. This information is communicated to an engine controller, which in turn determines the amount of power that should be supplied in response to a vehicle operator's request. Typically, the controller utilizes a look-up table that lists set engine responses for each accelerator pedal position. This engine control response originated from a system that utilized the direct mechanical connection where a set pedal position corresponded to a specific carburetor position, i.e. specific engine power response.
In the past, some engine management systems have used accelerator pedal position with current engine speed to determine the engine power set point. In response to a driver power request, the pedal position and engine speed are compared in a look-up table to determine a factor of the available engine power. One disadvantage with these ETC systems is that the systems are not capable of modifying engine power output to accommodate different driving applications or different driving habits.
There is a need for an engine management system that can accommodate driving differences. Because there is no direct mechanical connection with an ETC, it is possible to vary the response of the engine. This means that the same engine can be used in a variety of different vehicle applications by using an adaptive engine management system, which adjusts engine power output based on past driving tendencies and habits as well as using traditional ETC inputs. For example, the same engine may be used in different trucks that range from light duty trucks to heavy duty trucks. This engine may be slightly over-powered for the light duty trucks and slightly under-powered for the heavy duty trucks. Further, an aggressive driver of a heavy vehicle might drive differently than a non-aggressive driver of a lighter vehicle.
Thus, there is a need to vary the response of the engine to give the aggressive driver more response for a given accelerator pedal position while the non-aggressive driver would be given less response for that same pedal position. The engine management should be capable of learning and storing driver habits and tendencies over time to provide an adaptive engine output. A varied response is beneficial because it provides more resolution above and below nominal operating limits.